The x-ray tube has become common in medical diagnostic imaging, medical therapy, and various medical testing and material analysis industries. Such equipment is commonly employed in areas such as medical diagnostic examination, therapeutic radiology, semiconductor fabrication, and materials analysis.
An x-ray tube typically includes an evacuated enclosure within which a cathode and an anode are positioned. The cathode of the x-ray tube generally includes a source of highly energized electrons. The anode of the x-ray tube includes a focal track, which is generally manufactured from a refractory metal such as tungsten and is oriented to receive electrons emitted by the cathode.
During operation of the x-ray tube, the cathode may be charged with a current that causes electrons to “boil” off the electron source by the process of thermionic emission. An electric potential can be applied between the cathode and the anode in order to accelerate electrons emitted by the electron source toward the focal track of the anode. X-rays are generated when the highly accelerated electrons strike the focal track. Some of the x-rays that are produced by these processes ultimately exit the x-ray tube through a window and interact with a patient, a material sample, or another object.
It is generally desirable to maximize the focusing of the electron stream on the anode surface in order to produce a tightly collimated x-ray beam. It is well understood that the quality of diagnostic images additionally depends on the pattern, or focal spot, created by the emitted beam of electrons from the cathode onto the focal track of the anode. In general, a smaller focal spot produces a more highly focused or collimated beam of x-rays, which in turn produces better quality x-ray images.
The characteristics of the focal spot may be affected by the configuration of the components of the cathode. However, many cathode assemblies are configured in such a way that they impair the effectiveness with which the focal spot can be defined and/or maintained.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.